The invention is related to an adsorption unit of an intake manifold for combustion gas of an internal combustion engine, in particular of a motor vehicle, for adsorption of products of incomplete combustion such as hydrocarbons. The adsorption unit is arranged in an intake conduit of the intake manifold and includes an adsorption element made of an adsorption medium that is formed to a hollow body that encloses an interior of the adsorption element and is open at two opposite ends and through which a main flow passage of the combustion gas extends.
Moreover, the invention concerns an absorption muffler of an intake manifold for combustion gas of an internal combustion engine, in particular of a motor vehicle, for muffling intake noise during intake of the combustion gas. The absorption muffler is arranged in an intake conduit of the intake manifold and comprises a muffler element made of a sound-absorbing medium that is formed to a hollow body that encloses an interior of the muffler element and is open at two opposite ends and through which a main flow passage of the combustion gas extends.
Moreover, the invention concerns an intake manifold for combustion gas of an internal combustion engine.
DE 20 2006 007 096 U1 discloses an intake manifold of an internal combustion engine with integrated air filter that is flowed through by inflowing combustion air. After filtration, the combustion air is supplied downstream of the air filter to the cylinder inlets of the internal combustion engine. In order to prevent that after shutdown of the internal combustion engine fuel vapors can flow back through open inlet valves into the intake manifold and are accidentally released into the atmosphere, between the air filter and the cylinder inlets in the intake manifold an adsorption unit is arranged that adsorbs the fuel vapors. The adsorption unit has an adsorption element made of an adsorption medium formed to a hollow cylinder. The adsorption medium delimits an interior with an axial flow passage for the combustion air. When the internal combustion engine is turned off, the hydrocarbons can basically propagate via the axial flow passage also in opposite direction and deposit on the inner boundary walls of the adsorption medium where adsorption takes place. In regular operation, on the other hand, i.e., when the flow of combustion air is guided into the cylinder inlets of the internal combustion engine, desorption of the combustion residues at the inner wall of the adsorption element takes place. In this way, the adsorption element is subjected to regeneration in order to adsorb hydrocarbons again during the next standstill of the internal combustion engine. Over the course of time, however, combustion residues can settle in the radial outer area of the inner side of the adsorption medium so that gradually loading of the adsorption material with hydrocarbons increases and the adsorption capability decreases.